Gnathodynamometer



Dec. 8,1942, Boos 75 GNATHODYNAMQMETER Filed Jan. 21; 1959 2 Sheets-Sheet 1 Ra'Lph'H. Boos Dec. 8, 1 942. I oos 2,304,675

GNATHODYNAMOMETER Filed Jan. 21, 1939 2 Sh eets-Sheet 2 Phi-5 o Ill;

gvwwwtow Patented Dec. 8, 1942 UNITED STATES PATENT. QFFICE 2,304,675 GNATHODYNAMOMETER Ralph H. Boos, Hopkins, Minn.

Application January 21, 1939, Serial No. 252,171

14 Claims.

My invention relates to gnathodynamometers and has for an object to provide a device by means of which dentures may be constructed for edentulous mouths so that maximum efliciency and greatest comfort to the user results.

Another object of the invention resides in providing a device by means of which the pressure exerted between the human jaws may be easily and accurately measured.

A further object of the invention resides in providing a gnathodynamometer in which the measurement of the pressure exerted by the jaws may be measured at different amounts of opening of the jaws.

Another object of the invention resides in providing a device in which a mounting is employed which is adapted to be attached to a denture base applied to one of the jaws of the patient and including an engaging member carried by the mounting and disposed within the mouth.

A still further object of the invention resides in providing a fixed member for application to the denture base carried by the other jaw and adapted to be engaged by said engaging member.

A still further object of the invention resides in providing means acting between said mounting and engaging member for guiding one thereof for movement relative to the other in the direction of movement of the jaws and in further providing resilient means acting therebetween for resisting closing of the jaws.

An object of the invention resides in providing indicating means operated by relative movement between said engaging member and said mounting and having an indicating member disposed exteriorally of the mouth. A feature of the invention resides in constructing the mounting with a tubular housing having a movable member therein for moving said indicating member.

Another object of the invention resides in providing a locking device for holding the engaging member in any desired position with reference to the mounting.

An object of the invention resides in constructing the engaging member with a part adjustable in the direction of movement thereof so as to permit of measuring the pressure at different amounts of opening of the jaws of the patient.

Another object of the invention resides in utilizing a plunger having a cap threaded thereon and adjustable lengthwise of the plunger.

A feature of the invention resides in employing a rack movable with the plunger and inutilizing a shaft having a pinion meshing withsaid rack and operating a pointer for indicating the pressure applied to the engaging member.

A still further object of the invention resides in employing a tubular housing through which said shaft extends, said housing being connected to the body of the mounting and extending outwardly through the mouth of the patient to expose the pointer exteriorally of the mouth of the patient.

Another object of the invention resides in employing a threaded member for operating the locking device and in extending said thread member outwardly through the mouth of the patient.

Other objects of the invention reside in the novel combination and arrangement of parts and in the details of construction hereinafter illustrated and/or described.

In the drawings: 1

vFig. 1 is an elevational view of a gnathodynamometer constructed in accordancev with my invention and illustrated as applied to a set of denture bases.

Fig. 2 is a front view of the invention detached from the denture bases.

, Fig. 3 is a plan view of the invention as shown in Fig. 2.

Fig. 4 is a plan view of the invention drawn to an enlarged scale and showing parts thereof in section.

Fig. 5 is an elevational sectional view taken on line 55 of Fig. 4.

Fig. 6 is an elevational sectional view taken on line 66 of Fig. 4.

Fig. '7 is a perspective view of the plunger 0! the invention.

Fig. 8 is a perspective view of the locking bolt of the invention.

In the construction of dentures for edentulous mouths it is possible to build the dentures to occlude at difi'erent'amounts of opening of the jaws. It has been observed that, where the amount of opening is that which is natural to the patient, greater pressure can be exerted by the patient and consequently greater comfort results in the use of the dentures. Heretofore no exact method has been in common use for accurately determining the exact amount of opening of the mouth at which occlusion should take place. The present invention provides a device whereby the exact position of the jaws may be determined at which maximum pressure can be procured in biting and by means of which dentures may be constructed which occlude when the jaws are substantially at such position or some other suitable position determined therefrom to give the most comfort and service to the patient.

For the purpose of illustrating the application of my invention I have shown in Fig. 1 an upper denture base H! which is applied to an upper jaw model II. The corresponding denture base for the lower jaw is indicated at 13 which is mounted on a lower jaw model l4. Since the construction of such bases and models is well known in the art, the method of constructing the same will not be described in this application for patent though it can be readily comprehended that the models and bases may be made by taking impressiom of the jaws and casting and forming the same in accordance with the usual practice. In the construction of the dentures the models I! and M are mounted upon an articulator which has not L been shown in the drawings and the dentures built in the customary manner.

My invention proper comprises a mounting 20 which is disposed within the mouth of the-patient and is attached to the lower denture base I3; This mounting carries an engaging member l9 which is movable in the direction of movement of the jaws of the patient. The member l9 engages a plate 2| carried by the upper denture base In. Movement of the engaging member 19 is resisted through resilient means and the pressure imparted to the engaging member 19 is indicated by an indicating. device designated in its entirety by the reference numeral. 22 which is. situated at the end of the tubular housing l5 and is positioned exteriorally of the mouth of the pa.- tient. A locking device 23 controlled exteriorally of the patients mouth, holds the engaging member I9 in any desired position so that, when the proper position of the jaws is determined at which the maximum pressure may be exerted, the said position may be retained so that the models and denture bases may be subsequently mounted upon an articulator in proper relation preparatory to the construction of the dentures. These various parts will now be described in detail.

The mounting includes a body I5 which is disposed within the mouth of the patient near the center of the same and which has attached to the forward portion thereof a tubular housing l6. Issuing laterally and rearwardly from the body iii are two arms H and [8. The two arms I1 and I8 and the tubular housing IS form a support for the invention proper and are adapted to be attached to the denture base l3 in a mannor to be subsequently more fully described so as to give uniform pressure throughout the denture base.

The body N5 of the gnathodynamometer is tubular in form, being constructed with a bore 24 open at the upper end of the same and closed at the lower end through a bottom 25 forming a part of the said body. In this bore is slidably mounted a plunger 26, the upper end 2? of which projects outwardly beyond the upper end of the body 15. This portion of the plunger is reduced in diameter and is threaded as indicated at 28. The plunger 26 is formed with a longitudinally extending cavity 29 therein. In this cavity is mounted a. compression coil spring 3! which is seated at one end against the bottom 25 of the body !5 and at its other end against an abutment 32 in the end 2! of plunger 26. Screwed upon the threaded end 21 of the plunger 26 is a cap 33, which cap is knurled upon the exterior thereof as designated at 34 and which is provided with a conical point which forms the engaging member l9, previously referred to. This engaging member is adapted to engage the plate or abutment 2!. When the gnathodynamometer is mounted in the mouth, pressure between the jaws is transmitted from the plate 21 to the engaging member Hi which procure relative movement between the plunger 25 and body l5 along the bore 24. thereof and against the action of the spring 3!. The diameter of the plunger 26 is slightly greater than the diameter of the cap 33 so that a shoulder 36 is formed at the juncture of the end 2'! with said plunger, which shoulder projects outwardly beyond the cap 33. For holding the plunger 26 in position a cover plate 31 is employed which has a circular opening 38 in it slightly larger in diameter than the diameter of the cap 33 but small enough to cause the said plate to engage the shoulder 36 of plunger 26. This limits upward movement of the plunger and prevents the plunger from being unintentionally disengaged from the bore 26. The cover plate 3'? is held attached to the body 15 by means of three screws 38 which extend through said plate and are screwed into the body l5.

The indicating device 22 utilizes the tubular housing Hi. This housing is constructed at one end with a threaded part 39, which is screwed into a boss ii formed on the body I5. The boss 4| is constructed with a compartment 42 into which the part 3% is screwed and which communicates with the bore 24. Rotatably mounted Within the tubular housing it is a shaft 43. This shaft has secured to the inner end of it a small pinion 44 which meshes with a rack 45. Rack 45 is cylindrical in form and is mounted for vertical movement in a second bore 46 formed in the body l5, which bore is parallel with the bore 24 but spaced therefrom. A slot 47 connects the two bores together. The rack 45 is reciprocated within its bore by means of a pin 43 which extends transversely through both the plunger 26 and the said rack. It will readily be comprehended that, as the plunger 23 is reciprocated within its bore, rack $5 is caused to move with it and as the said rack moves the pinion 44 is rotated and correspondingly shaft 43 rotated.

The indicating device 22 further includes a dial 49 which is attached to the end of the tubular housing It and which is disposed exteriorly of the mouth of the patient. This dial is provided with graduations 5i which may be calibrated to read in pounds pressure or in any other units desired. Rotatably mounted on the protruding end of the shaft 43 is a pointer 52 which is adapted to indicate the maximum pressure applied to the device. Rigidly secured to the outer end of the shaft 43 is another pointer 53 which is disposed in a plane outwardly of that of the pointer 52 but which travels over the same course. The pointer 52 has a lug 54 extending outwardly therefrom which is adapted to be engaged by the pointer 53. When pointer 53 moves in a clockwise direction, as viewed in Fig. 2, pointer 52 is carried with it. When pointer 53 returns to zero position, pointer 52 remains and indicates the pressure last applied to the engaging member The locking device 23 includes a bolt 55 which is shown in detail in Fig. 8. Thi bolt is constructed from a rod threaded at its outer end as designated at 56. The other end portion of this rod is cut away at 51 to provide a tapered cam 58 at the end of the same. The bolt 55 is mounted for reciprocation within a bore 59 which intersects the bore 24 and which is situated substantially at right angles thereto. The periphery of the plunger 26 is formed with a tapered surface 6|, best shown in Fig. '7. The bore 59 is so situated that the cam 58 comes opposite the surface 6 I. By drawing the bolt 55 outwardly along the bore 59 cam 58 is brought into engagement with the surface 6| and the plunger 26 is locked in position. -In order to move the bolt 55, a spindle 62 is employed which is bored and threaded at one end as designated at 63 to screw upon the threads 56 of bolt 55. This spindle is constructed with a shoulder 64 which engages a corresponding shoulder 65 on the body 55, which shoulder encircles the end of the bore 59. The spindle 62 has secured to the end of it a knurled head 66 by means of which the same may be rotated. It will readily be comprehended that, as the spindle 52 is rotated in a clockwise direction, the shoulder 54 engages the shoulder 95 and the bolt 55 is drawn along the bore 69 to force the cam 58 into engagement withthe tapered surface 6| of the plunger 26. This holds the plunger in locked position.

The method of using the invention is as follows: Impressions are taken of the mouth of the patient and the jaws. The models H and 54 are constructed therefrom. The denture bases and I3 are next formed on the jaw models which maybe made of gutta-percha or resin, vulcanite or any other suitable composition such asis now used for the purpose. The gnathodynamometer is next placed upon the lower denture base lit with the arms I! and I 8 extending across the buccal portions of the same and With the tubular housing l6 extending across the labial portion of said denture base. The mounting is then leveled up and attached to the denture base l3 by a suitable compound, the said mounting being positioned so that the engaging member i9 is substantially in the center of the area of the jaw ridge and so that the spring 35 is substantially in the medial plane of the patient. The abutment of plate 2! is next mounted in the hollow of the denture base H) by means of a suitable compound, plaster of Paris, or some other suitable material so that the same occupies a position substantially parallel with the plane of the use. The cap 33 is next lowered by screwing it downward on the plunger 26 and the bases are placed in the mouth of the patient. The patient is instructed to move the jaws laterally and protrusively with the engaging member E9 in contact with the plate 2|. This makes marks on the said plate and the outline of the tracings defines the limits of movement of the mandible. The patient is then requested to position the'jaws naturally and to exert maximum pressure. This forces the plunger 26 into the bore 24 and compresses spring 3l. Movement of the plunger causes movement of rack with corresponding rotation of the shaft 43 and pointer 53. When the patient releases the pressure pointer 52 indi cates the pressure exerted. The cap i9 i next raised slightly and the same procedure repeated. Another reading is taken and compared with the first reading. If the second reading is equal to or greater than the first reading the procedure is repeated, the cap 33 being raised each time. The pressure exerted at various amounts of opening of the jaws is thus accurately measured and it will be found that at one particular opening greater pressure can be exerted than at any other degrees of opening. When this degree of opening is reached, the plunger 26 is locked in position by rotating the'head 66 of spindle 62 and drawing the bolt 55 up against said plunger to restrain movement thereof. After such position of the jaws is determined the patient is requested to shift the jaws laterally and protrusively and measurements of the pressure exerted by the patient at such positions also taken. A locality in the occlusal plane may thus be found at which maximum pressure can be exerted by the patient. The two denture bases are next firmly secured in the determined positions by means of plaster of Paris, wax compound or any other material before'being removed from the mouth. After being locked in position the denture bases are removed from the mouth and mounted in an articulator. Thereafter the dentures are constructed in the customary manner, account being taken of the lateral or protrusive position if the relation is not centric. If, on successively raising the cap 33, the pressure has become less, then the plate 2! must be re-set deeper into the denture base l0 and the operations repeated. If on the other hand the pressure keeps increasing when the cap is raised but never decreases, then the'plate must be re-set in the denture base ID less deeply. In the mounting of the jaw models II and I4 on the articulator the articulator may be adjusted or the models may be mounted so that the engaging member l9 occupies a definite relation with respect to the tracings formed on the plate 2i. In this manner the proper position of the jaws laterally, protrusively and in elevation may be determined so that, when the dentures are subsequently constructed, the same will properly fit within the mouth, operate to give maximum pressure when in occlusion and give greatest comfort to the patient,

My invention is simple and practical in construction. The operating parts are so constructed and disposed as to be readily applicable to the denture bases. The actuating mechanism is so constructed as to be positioned within the mouth of the patient where the stresses are directly applied to the same and the indicating device is positioned exteriorally of the mouth where the same may be readily viewed by the user.

, Changes in the specific form of my invention, as herein disclosed, may be made within the scope of what is claimed without departing from the spirit of my invention.

Having described my invention, what I claim as new and desire to protect by Letters Patent is:

1. A gnathodynamometer comprising a mounting for application to one of the jaws, an engaging member carried by said mounting and adapted to be positioned within the mouth, said engaging member and mounting being guided for relative movement in the direction of movement of the jaws, a fixed member for application to the other jaw and disposed within the mouth and adapted to be engaged by said engaging member, resilient means acting between said mounting and engaging member for yieldingly resisting relative movement therebetween, and indicating means including a shaft rotated through relative movement between said mounting and engaging member, said shaft extending through the mouth and a pointer on said shaft disposed exteriorly of the mouth.

2. A gnathodynamometer comprising a mounting for application to one of the jaws, a plunger adapted to be positioned within the mouth, said plunger and mounting being guided for relative movement in the direction of movement of the jaws, a fixed member for application to the other jaw, means on said plunger for engagement with said fixed member, resilient means acting between said mounting and plunger for yieldingly resisting relative movement therebetween, a rack movable with said plunger, a shaft carried by said mounting and extending through the mouth, a pinion on said shaft engaging said rack and indicating means disposed .exteriorly of the mouth and operated by said shaft.

3. A gnathodynamometer comprising a mounting having a body, a tubular housing extending therefrom and two arms laterally disposed with respect to said tubular housing, said tubular housing and arms being disposed substantially in. a single plane and being adapted to be attached to a denture base fitting one of the jaws, an engaging member carried by said mounting, said mounting and engaging member being guided for relative movement in the direction of movement of the jaws, a fixed member adapted to be attached to the other denture base and adapted to be engaged by said engaging member, means acting between said mounting and engaging member for yieldingly resisting relative movement therebetween and indicating means including a rigid movable member disposed within said tubular housing and operated through relative movement between said mounting and engaging member, said indicating means including an indicating member at the end of said tubular housing.

4. A gnathodynamometer comprising a mounting for application to one of the jaws, a plunger, said plunger and mounting being guided for relative movement in the direction of movement of the jaws, a fixed member for application to the other jaw, means on said plunger for engaging said fixed member, resilient means acting between said mounting and plunger for yieldingly resisting relative movement therebetween, indicating means operable through relative movement of said mounting and plunger for indicating the pressure applied to said engaging member, said plunger having a tapered surface and a cam carried by said mounting and guided for movement into engagement with said tapered surface, and means for moving said cam to restrain relative movement between the mounting and plunger.

5. A gnathodynamometer comprising a mounting for application to one of the jaws, an engaging member carried by said mounting, said engaging member and mounting being guided for relative movement in the direction of movement of the jaws, a fixed member for application to the other jaw and adapted to be engaged by said engaging member, means acting between said mounting and engaging member for yieldingly resisting relative movement therebetween, indicating means operated through relative movement between said mounting and engaging member for indicating the pressure applied to said engaging member, said indicating means including a shaft extending through the mouth, a dial disposed exteriorly of the mouth, means extending through the mouth and carried by said mounting for supporting said dial and a pointer on said shaft movable relative to said dial.

6. A gnathodynamometer comprising a mounting for application to one of the jaws, a plunger, said plunger and mounting being guided for relative movement in the direction of movement of the jaws, a fixed member for application to the other jaw, means on said plunger for engaging said fixed member, resilient means acting between said mounting and plunger for yieldingly resisting relative movement therebetween, indicating means operable through relative movement of said mounting, and plunger for indicating the pressure applied to said engaging means, said plunger having a tapered surface and a am carried by said mounting and guided for movement into engagement with said tapered surface, said cam restraining relative movement between the mounting and plunger, and a threaded member for engagement with said cam for advancing said cam relative to the tapered surface, said threaded member extending through the mouth and being operable exteriorly of the mouth.

7. A gnathodynamometer comprising a mounting for application to one of the jaws, a plunger, said plunger and mounting being guided for relative movement in the direction of movement of the jaws, a fixed member for application to the other jaw, means on said plunger for engaging said fixed member, resilient means acting between said mounting and plunger for yieldingly resisting relative movement therebetween, indicating means operable through relative movement of said mounting and plunger for indicating the pressure applied to said engaging member, said plunger having a tapered surface and a threaded bolt reciprocable transversely of said plunger and having a cam at one end for engagement with said tapered surface to lock the plunger from movement and a threaded member screwed upon the threaded bolt for advancing the bolt into locking position.

8. A gnathodynamometer comprising a mounting for application to one of the jaws, a plunger, said plunger and mounting being guided for relative movement in the direction of movement of the jaws, a fixed member for application to the other jaw, means on said plunger for engaging said fixed member, resilient means acting between said mounting and plunger for yieldingly resisting relative movement therebetween, said plunger having a tapered surface, a locking device including a bolt having a cam for engagement with said tapered surface, and means for moving said cam into engagement with said tapered surface to restrain movement of the plunger by said resilient means.

9. A gnathodynamometer comprising a mounting for application to one of the jaws, a single engaging member carried by said mounting and adapted to be positioned substantially centrally within the arch of the jaws, said engaging member and mounting being guided for relative movement in the direction of movement 'of the jaws, a fixed member for application to the other jaw and adapted to be engaged by said engaging member at a single locality, means acting between said mounting and engaging member for yieldingly resisting relative movement therebetween, indicating means operated through relative movement between said mounting and engaging member for indicating the pressure applied to said engaging member, and means for varying the initial position of said engaging member relative to the mounting to accommodate measurement of pressure exerted by the jaws at various amounts of opening thereof.

10. A gnathodynamometer comprising a mounting for application to one of the jaws of a patient including a tubular member, a second tubular member slidable relative to said first tubular member, resilient means disposed within said tubular members and acting to restrain movement of said members toward one another, a third tubular member movable along said second tubular member, a fixed member for application to the other jaw of the patient, means on said third tubular member for engaging said fixed member, means for holding said third tubular member in fixed position relative to said second tubular member, means for holding said second tubular member fixed relative to said first tubular member, and indicating means operated through relative movement of first and second tubular members.

11. In combination a gnathodynamometer adapted to be positioned within the mouth of a patient comprising a mounting applied to one of the jaws, a movable member carried by said mounting, said member and mounting being guided for relative movement in the direction of movement of the jaws, a fixed member applied to the other jaw, an engaging member carried by said movable member and adapted to engage the fixed member appliedto the other jaw, a spring acting between said mounting and movable member and having sufiicient rigidity to resist the maximum pressure capable of being exerted by the jaws of the patient, said mounting and spring being disposed within the mouth of the patient substantially in the medial plane of the patient, indicating means operated by relative movement between said mounting and movable member for indicating the pressure resisted by said spring, and means for locking said movable member relative to said mounting, said locking means having an operating member extending through the mouth.

12. A gnathodynamometer comprising a mounting for application to one of the jaws of the patient and a fixed member for application to the other of the jaws of the patient, said mounting having a bore extending in the direction of movement of the jaws of the patient, a tubular plunger slidable within said bore and having a portion extending outwardly beyond said mounting, a compression spring disposed within said plunger and bore and resisting relative movement therebetween and a tubular cap screwed upon the protruding end of said plunger for extending the length thereof, means on said cap for engagement withsaid fixed member, means for locking said plunger from movement relative to said mounting, and indicating means operated by relative movement between said plunger and mounting.

13. A gnathodynamometer comprising a mounting for application to one of the jaws, an engaging member carried by said mounting and adapted to be positioned within the mouth, said engaging member and mounting being guided for relative movement in the direction of movement of the jaws, a fixed member for application to the other jaw and disposed within the mouth and adapted to be engaged by said engaging member, resilient means acting between said mounting and engaging member for yieldingly resisting relative movement therebetween, and indicating means including a shaft rotated through relative movement between said mounting and engaging member, said shaft extending through the mouth and indicating means disposed exteriorly of the mouth at the end of the shaft and operated thereby.

14. A gnathodynamometer comprising a mounting for application to one of the jaws, a plunger, said plunger and mounting being guided for relative movement in the direction of movement of the jaws, a fixed member for application to the other jaw, the outer end of said plunger being threaded upon the exterior thereof, a cap screwed on said plunger and movable relative thereto in the direction of movement of the jaws, said cap being free from said mounting and adjustable relative to the plunger independently of the mounting, said cap having a part adapted to engage said fixed member, a coil spring disposed within said plunger and mounting and extending into the threaded-part of said plunger for yieldingly resisting relative movement between said cap and mounting and indicating means operated through relative movement of said mounting and plunger for indicating the pressure applied to said plunger.

RALPH H. BOOS. 

